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Incorrect Light Distribution from Light Fixtures

Posted on March 5th, 2019. Last updated on June 14th, 2023.

Problem: The light distribution from one of your light fixtures does not extend in the right direction relative to the block and/or does not originate from the correct point on the block.

Cause: There is an incongruity between your light fixture block and the IES file associated with it.

Typically, IES files extend in the direction of angle 0, which is the same direction most blocks face. If the file was not oriented correctly, the light distribution will extend at an odd angle from the block.

The origin of the light distribution is determined by the Design Master attribute CON_CENTER, or the insertion point if the attribute is not present. If the origin is not correct (for example, a block for a lamp mounted to a pole has its origin at the pole), the light distribution will not be correct.

Solution 1: Account for the differences in the Light Fixture Project Schedule. This solution allows you to change the light fixture for a given IES file in the current project without affecting the block definition.

In this dialog box, the IES Rotation value rotates the light distribution. The Arm Length value moves the light distribution origin in the direction of the rotation angle.

Solution 2: Account for the differences by making changes to the block using the Open Block from Drawing command. This solution allows you to modify the block so it will always work with a particular IES file.

Select the block you want to change.

If the direction is off, rotate the block to match the light distribution.

If the origin is off, move the CON_CENTER attribute to the correct location or, if the attribute is not present, move the block so the insertion point is centered on the correct location.

Save the block, then run the Redefine Block in this Drawing command and select the light fixture block.

The block will update to reflect the changes. Continue making changes until the block and light distribution line up correctly.

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